Method of making screen plates



May 24, 1932. w. E. M MURRAY METHOD OF MAKING SCREEN PLATES Filed Sept.4, 1930 5 Sheets-Sheet 1 Suva/" 6oz lV/IL TEE E. M MMF/EAY gaym zm w. E.M MURRAY 1,859,784

METHOD OF- MAKING SCREEN PLATES Filed Sept, 4, 1950 3 Sheets-Sheet 3 m w5% m/y////v/// W NP mm awweutoz Patented May 24, 1932 UNITED STATESPATENT. OFFICE \VALTER E. MCMURRAY; OF CLEARFIELD, PENNSYLVANIA,ASSIGNOR T0 CLEARFIELD MACHINE COMPANY, OF GLEARFIELD, PENNSYLVANIA, ACORPORATION OF PENN- SYLVANIA METHOD MAKING SCREEN PLATES This inventionrelates more especially to screen plates 1n WlllCh the screening slotsare of arcuate form and concentrically arrangedwith respect to a commonaxis of revolution.

The primary object of my invention is to provide an improved. method forconstructing screen plates of this character for the pur- I vide animproved method for constructing.

segmental screen plates from predetermined lengths of straight bars ofproper form, said method contemplating the separate bending of saidstraight bar lengths which after flexure and assembling are rigidlyunited into a simple unitary structure.

In the drawings which represent a preferred embodiment of my inventionas ap-' plied to a screen for dry pans in rotary mills, Figure 1 is atop plan view of a screen plate constructed in accordance with theprinciple of this invention.

Figure '2 is a top plan View of the segmental supporting frame thereforwith the screen plate in position, portions offsaid screen plate beingbroken away.

Figure 3 is an enlarged radial section of the screen plate andsupporting frame on the line'3-3, of Figure 2. v

Figure 4 is an enlarged endelevation of Figure 2. i F

Figure 5 is a top plan view of a preferred form of jig or former withinwhich the straight bars or blanks are curved or bowed while they arebeing assembled in their' screen-forming arrangement some of the barsbeing shown in assembly position and another one shown in process ofbeing bowed and positioned. v I J Figure 6 is an enlarged end elevationof the Application filed September 4, 1930. Serial No. 479,649.

jig shown in Figure 5 with the screen bars 'to be inserted into thebending and assembling jig. 7 Figures 9, 10 and 11 are enlargedfragmentary representations of radial sections of the assembled screenbars showing different forms of welding which may be used'advantagcouslyfor joining the screen bars into a unitary structure. 7 I a In Figure 1of the drawings is shown an illustrative embodiment of a segmentalscreen plate to the construction of which my improved method may beadapted. As shown, this screen plate comprises a series of arcuatescreen bars 1 which are graded in length and concentrically arrangedwith their opposite ends in radial alinement, said arcuate bars beingrigidly united along the radial lines 2, 3, 4;, 5, and 6 by weldingopera tions as hereinafter described. In this way. the screen plate isprovided with radial bars which may be arranged to correspond with thesimilarly arranged bars of a supporting frame by which it is to becarried. At angularly-spaced intervals around the outer and innerperipheries of the screen plate, inserts are welded in between some ofthe arcuate bars 1 in such a way as to form attachment bosses 7 and 8.All of the bosses thus formed are adapted to be arranged above and to beconnected to similarly arranged bosses with which said supporting frameis provided." As shown in Figures 3 and 4, the screen bars 1 areprovided with inverted cuneiform cross sections which provide downwardlyenlarged intervening slots As .shown in Figures 2, 3 and 4. theabove-described segment, screen plate is adapted tobe seated in a rotarysupporting frame segment which. comprises inner and outer arcuate bars 9and 10 and insaid arcuate bars being provided with annular seats 16 and17 for supporting the inner and outer arcuate edges of the screen plate.

It will be seen that when the screen plate is properly positioned on thearcuate supporting'framc, the radial bars of said screen plate which-areformed along the radial lines 2, 3,

4, 5 and 6, will be arranged over and rest upon .the upper edges .of theradial bars .11, .12, 13, 14 and 15 of the supportingframe segment. Saidframe segment may be provided with apertured bosses 18, arrangedrespectively below the attachment bosses 7 of the screen plate and otherapertured bosses 19 arranged 15 respectively below the attachment bosses8 of said'screen-plate. Asindicatedin Figure 3 of the drawings,abolt;'2O may be'passed upwardly"through.each. of the apertured bosses18"and 19 and have-their upper ends 0' threaded into tller-TGSPGCtiVG:attachment.

\ bosses 7 and 8- of the-screen plate." Suitable --uneans formanufacturing the screen-plate .describedabove;from straight bars ofproper cross section and graded in length, "may be ggwprovidedasfollows. "A-group of ','straight bars suitably'zgradedi in: lengthsto'malre up thedesiredscreen :plate, isshown in Figure 8.

:;Referring now to Figures 5, 6- and 7gthe straight bars or blankszshownin'Figure 8,

" may be bent and assembled in aji such as that shownzin Figures 5, 6:and 7. For this purpose, a heavy flatbase' plate 21 which is lon'gerandwi'der than the completed-screen plate, imay-be provided with aradial edge 22 85 withwhich the alined endszoftall'screen bars willregister when saidscreenbars have their opposite ends in abutment with aradial strip or stop bar 23: which issecured to theiother ra'dialedge'of the base plate 21 by means of 10 bolts-2 lasshown in Figure7.--Spaced in- :wardly fromthe radial edge 22 of the base #plate 21 andremovably securedthereto bybolts 25,-as shown in Figure 6,'isa gagebar26 which is providediwith a series of downand shape to permit theseveral straight bar sections or blanks to be driven endwise there--through, said notches being uniformly spaced one fromanothertocorrespon'd to the spacingo-f thearcuate screen'bars in thefinished screen plate." Spacedinwardly from the stop bar'23, is a secondgage bar 28 of exactly siinilar'form to'thegage-bar'26. Interposedbetween the gage bars 26 and 28, are a plurali 'ity of laterally-spacedgage bars29, 30 and 31, similar inconstruction to the gage bars -'26 and 28,andarrangerLinpairs as" shown in r Figure 5. All of thegage barsare removably secured to the base plate 21 so as to permit C3thGTQIDOVELl of the finished screen plate after the several screen barshave been united into aunitary'structure in the manner to be pres.-ently explained. As each of said screen bars is tapped through one'afteranother of the notches" 27 ineach arcuately arranged series of saidnotches, the forward end of that screen bar is continually deflectedinto position to enter the notch next in front so that by the time ithas come into abutment with the stop bar 23, it has become bowed intoits arcuate form of the finished screen plate. It will be understoodfrom this description that after all of the screen bars have been drivenhome with their forward ends alined against the radial stop-bar 23,their rear ends will also be in alinenient along theradial edge 22 ofthe base plate 21. Said bars are now assembled in position to be rigidlyunited into a unitary structure. For this purpose, I preferably employany approved method of welding for uniting spaced bars of thischaracter,the necessary welding operations inthe present case beingperformed alongthe radial lines 2, 3, 4,5 and 6 w-lnchrespectively correeach of theradial lines 2, 3,4,5 and 6, the

adjacent spaces being filled by'the welding stock 33; If preferred, theintervening spaces between the neighboring bars may be completely filledwith small separateamasses 34:

' of the welding stock as shown innFigure 10.

According to Figure 111,-the spaces intervening betweenstie'screen: bars1 arezfilled by wedge-shaped blocks 35 which may be :brazed to theadjacent rods.

' While I have described a preferredanethod of procedure in respect to:cutting the straight screen bars in accurately gradedlengths so thatwhen flexed' and positioned inproperly :spaced relation, their endswill-come into radial alinement to correspond with-the radial -ends'of-the' finished segmental screen-plate,

45 wardly-enlarged-notches 27 of suitable size' the straightscreen barsmay be'flexedandpositioned prlor to a cutt1ng-operat1on along either orboth radial lines corresponding to the'ends 'of'the finished screenplate. Furthermore, I desire to have it understood. that theproper-lengths of-the. several screen bars may be determined by acutting operation by a cutting torchHor other suitable means before thewelding operation and while said screen bars are ;held in flexedposition,1or the screen plate may be finished or by a trimming operationalong its .radial edges after the welding operation is completed.

I claim: I 1. The method of constructingv segmental screen plates, whichmethod. consists in cutting a plurality of straight barsin lengthscorresponding respectively to. the lengths of said barsin a completedscreen plate, in areaately bending said bars, in" arranging said bars inproper spaced relations corresponding to their relative positions in thecompleted screen plate by means of the bending operation, and finally inrigidly uniting said bars together at longitudinally spaced points.

2. The method of constructing segmental screen plates, which methodconsists in cutting a plurality of straight bars in lengthscorresponding substantially to the lengths of the arcs formed by saidbars in the completed screen plate, in bending said bars into theirfinal arcuate form, and in assembling them in their final relativepositions during the progress of the bending operation, and finally inpermanently uniting said bars together.

3. The method of constructing segmental screen plates, which methodconsists in cutting a plurality of straight bars in lengthscorresponding respectively to' the lengths of the arcs formed by saidbars in the completed screen plate, in bending each of said bars intoits final arcuate form under a stress less than that required topermanently distort it, and finally in permanently uniting said barstogether while they are held in spaced flexed positions. 7

at. The method of constructing segmental screen plates, which methodconsists in cutting a plurality of straight bars in graded lengthscorresponding respectively to the lengths of arcuate screen-bars in asegmental screen plate in bending said bars into concentric arcs whilearranging them in equidistant positions between the inner and outerperipheries of the completed segmental screen plate, and finally, inpermanently uniting said arcuate screen bars to form a unitary screenplate.

5. The method of constructing segmental screen plates, which methodconsists in cutting a plurality of straight bars in lengthscorresponding respectively to the lengths of the arcuate bars in asegmental screen, in arcuately bending the longest of said bars whileplacing it in position to form the outer border of said segmentalscreen, in arcuately bending the shortest of said bars While placing itin position to form the inner border of said segmental screen, inbending the remaining bars in concentric arcs of graded lengths whileplacing them in equi-spaced positions between said inner and outerborders and with their opposite ends in radial alinement, and finally,in uniting the radiallyalined ends of said arcuate screen bars to form aunitary segmental screen plate.

6. The method of constructing segmental screen plates, which methodconsists in cut ting straight bars in graded lengths, in flexing saidbars under insufficient stress to permanently distort them, and finallyin welding said bars together to form a unitary segmental screen plate.

7. The method of constructing segmental screen plates, which methodconsists in cutting a plurality of straight bars in lengthscorresponding respectively to the arcs occupied by said bars in afinished segmental screen plate, in flexing said straight bars to theirproper arcuate forms while arranging them in the relatively spacedrelations to be occupied by them in the completed screen plate, and inwelding said screen bars together along radial lines; corresponding tothe underlying bars of a supporting frame upon which the completedsegmental screen plate is to be superimposed.

8. The method of constructing segmental screen plates, ting a pluralityof straight bars in lengths corresponding respectively to the arcs of afinished segmental screen plate, in arcuately bending said straight barswhile arrangwhich method consists in cuting them in suitably spacedconcentric positions with their ends in radial alinement, and in Weldingsaid arcuate screen bars together along lines and at placescorresponding to the supporting surfaces of a supporting frame uponwhich the completed segmental screen plate is to be superimposed.

9. The method of constructing segmental screen plates, which methodconsists in flexing a plurality of straight screen bars of gradedlengths and similar cross-section with corresponding surfaces disposedin a common plane, in arranging said screen bars in parallelly-spacedrelations during the progress of the flexing operation, and in weldingthe flexed screen bars together in their grouped arrangement.

